generic: test extending sub-block AIO writes for races

This tests Brian Foster's fix for xfs:

   xfs: always drain dio before extending aio write submission

It launches four adjacent 1k IOs past EOF, then reads back
to see if we have 4k worth of the data we wrote, or something else -
possibly zeros from sub-block zeroing and eof racing.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Eric Sandeen
2015-10-14 14:19:31 +11:00
committed by Dave Chinner
parent c892a79edc
commit cef2e7a583
4 changed files with 241 additions and 0 deletions
+173
View File
@@ -0,0 +1,173 @@
/*
* Launch 4 sub-block AIOs past EOF and ensure that we don't see
* corruption from racing sub-block zeroing when they're complete.
*
* Copyright (C) 2015 Red Hat, Inc. All Rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <libaio.h>
/* Sized to allow 4 x 512 AIOs */
#define BUF_SIZE 2048
#define IO_PATTERN 0xab
void
dump_buffer(
void *buf,
off64_t offset,
ssize_t len)
{
int i, j;
char *p;
int new;
for (i = 0, p = (char *)buf; i < len; i += 16) {
char *s = p;
if (i && !memcmp(p, p - 16, 16)) {
new = 0;
} else {
if (i)
printf("*\n");
new = 1;
}
if (!new) {
p += 16;
continue;
}
printf("%08llx ", (unsigned long long)offset + i);
for (j = 0; j < 16 && i + j < len; j++, p++)
printf("%02x ", *p);
printf(" ");
for (j = 0; j < 16 && i + j < len; j++, s++) {
if (isalnum((int)*s))
printf("%c", *s);
else
printf(".");
}
printf("\n");
}
printf("%08llx\n", (unsigned long long)offset + i);
}
int main(int argc, char *argv[])
{
struct io_context *ctx = NULL;
struct io_event evs[4];
struct iocb iocb1, iocb2, iocb3, iocb4;
struct iocb *iocbs[] = { &iocb1, &iocb2, &iocb3, &iocb4 };
void *buf;
struct stat statbuf;
char cmp_buf[BUF_SIZE];
int fd, err = 0;
off_t eof;
fd = open(argv[1], O_DIRECT | O_CREAT | O_TRUNC | O_RDWR, 0600);
if (fd == -1) {
perror("open");
return 1;
}
err = posix_memalign(&buf, getpagesize(), BUF_SIZE);
if (err) {
fprintf(stderr, "error %s during %s\n",
strerror(err),
"posix_memalign");
return 1;
}
memset(cmp_buf, IO_PATTERN, BUF_SIZE);
err = io_setup(4, &ctx);
if (err) {
fprintf(stderr, "error %s during %s\n",
strerror(err),
"io_setup");
return 1;
}
eof = 0;
/* Keep extending until 8MB (fairly arbitrary) */
while (eof < 8 * 1024 * 1024) {
memset(buf, IO_PATTERN, BUF_SIZE);
fstat(fd, &statbuf);
eof = statbuf.st_size;
/*
* Split the buffer into multiple I/Os to send a mix of block
* aligned/unaligned writes as well as writes that start beyond
* the current EOF. This stresses things like inode size
* management and stale block zeroing for races and can lead to
* data corruption when not handled properly.
*/
io_prep_pwrite(&iocb1, fd, buf, BUF_SIZE/4, eof + 0*BUF_SIZE/4);
io_prep_pwrite(&iocb2, fd, buf, BUF_SIZE/4, eof + 1*BUF_SIZE/4);
io_prep_pwrite(&iocb3, fd, buf, BUF_SIZE/4, eof + 2*BUF_SIZE/4);
io_prep_pwrite(&iocb4, fd, buf, BUF_SIZE/4, eof + 3*BUF_SIZE/4);
err = io_submit(ctx, 4, iocbs);
if (err != 4) {
fprintf(stderr, "error %s during %s\n",
strerror(err),
"io_submit");
return 1;
}
err = io_getevents(ctx, 4, 4, evs, NULL);
if (err != 4) {
fprintf(stderr, "error %s during %s\n",
strerror(err),
"io_getevents");
return 1;
}
/*
* And then read it back.
*
* Using pread to keep it simple, but AIO has the same effect.
* eof is the prior eof; we just wrote BUF_SIZE more.
*/
if (pread(fd, buf, BUF_SIZE, eof) != BUF_SIZE) {
perror("pread");
return 1;
}
/*
* We launched 4 AIOs which, stitched together, should write
* a seamless BUF_SIZE worth of IO_PATTERN to the last block.
*/
if (memcmp(buf, cmp_buf, BUF_SIZE)) {
printf("corruption while extending from %ld\n", eof);
dump_buffer(buf, 0, BUF_SIZE);
return 1;
}
}
printf("Success, all done.\n");
return 0;
}
+65
View File
@@ -0,0 +1,65 @@
#! /bin/bash
# FS QA Test No. 114
#
# Test races while extending past EOF via sub-block AIO writes
#
#-----------------------------------------------------------------------
# Copyright (c) 2015 Red Hat, Inc. All Rights Reserved.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#-----------------------------------------------------------------------
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
here=`pwd`
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
cd /
rm -f $TEST_DIR/tst-aio-dio-eof-race
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
_supported_fs generic
_supported_os Linux
_require_test
_require_sparse_files
_require_aiodio aio-dio-eof-race
# Test does 512 byte DIO, so make sure that'll work
logical_block_size=`_min_dio_alignment $TEST_DEV`
if [ "$logical_block_size" -gt "512" ]; then
_notrun "device block size: $logical_block_size greater than 512"
fi
# We don't mind 512-byte fs blocks; the IOs won't be sub-block,
# but the test should still pass, even if it doesn't stress the code
# we're targeting.
# Note, this test does several extending loops internally
$AIO_TEST $TEST_DIR/tst-aio-dio-eof-race
status=$?
exit
+2
View File
@@ -0,0 +1,2 @@
QA output created by 114
Success, all done.
+1
View File
@@ -114,6 +114,7 @@
109 auto metadata dir
112 rw aio auto quick
113 rw aio auto quick
114 rw aio auto quick
117 attr auto quick
120 other auto quick
123 perms auto quick